JP2000228458A - Ball grid array semiconductor package, and its mounting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To raise the connection strength after mounting and the reliability, and also to dispense with the work in the process after connection. SOLUTION: This package is a BGA(ball grid array)-type semiconductor package or an LGA( land grid array)-type semiconductor package which is equipped with reinforcing leads for securing the fixation to a mounting board, at the two corners at least of a semiconductor package substrate 2. Here, the open end of the reinforcing lead installed at the corner of the substrate of the BGA-type semiconductor package 1 is inserted and soldered into the through hole being made in advance when it is mounted on the mounting board, or it is soldered in the specified section of the surface of the mounting board. Thus, this semiconductor package is reinforced to external stress.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball grid array (BGA) type semiconductor package or a land grid array (LGA).
The present invention relates to an id Array (hereinafter referred to as LGA) type semiconductor package and its mounting structure.

[0002]

2. Description of the Related Art In recent years, with the spread of portable electronic devices, such as mobile phones, various mobile tools, and notebook personal computers, there has been a demand for smaller and lighter devices. Under these circumstances, it is necessary to increase the density and integration of LSI chips. In response to this, LSI chips have become larger and have more pins, and demands for corresponding mounting structures have been increasing. .

Conventionally, in portable equipment, a BGA including a small package called CSP (chip size package) or FPBGA (fine pitch BGA) has been used.
For the purpose of improving strength and reliability after mounting, a method of applying a resin between a mounting substrate and a package or around a package and curing the die semiconductor package is adopted. However, this conventional technique has the following problems.

[0004] The first problem is that the number of working steps increases, and the manufacturing lead time and processing cost increase. After the automatic mounting process, the resin is applied around the BGA-type semiconductor package or between the BGA-type semiconductor package and the mounting board. After the application is completed, the resin is put into a curing furnace, and the resin is cured. This is because work is required.

[0005] The second problem is that, as described above, the resin curing step is required, so that the mounting substrate and the mounted components are not
Extra thermal stress or mechanical stress is applied. Normally, only heating by reflow in the automatic mounting process adds heating for resin curing, which causes problems such as warpage of the mounting board or quality deterioration due to thermal stress of the mounting board and mounted components. There is a risk of causing.

The third problem is that, by applying and curing the resin, the BGA type semiconductor package is partially repaired (repaired).
Is impossible. Generally, a thermosetting resin such as an epoxy resin is used as the resin, and therefore, once cured, it cannot be removed. Therefore, if a defect occurs even in a very small part of the mounted BGA type semiconductor package, it cannot be repaired, and the entire mounting substrate must be discarded.

[0007] Other conventional techniques, for example, Japanese Patent Laid-Open No. 9-30
Japanese Patent Application Publication No. 7022 discloses that, among the solder balls arranged in a matrix of a BGA type semiconductor package, a solder ball at an outermost portion is formed to have a larger diameter than a solder ball at an inner portion, thereby resulting in poor soldering. It can be prevented. However, in this conventional technique, since the diameter of the outermost solder ball is large, the height is higher than other solder balls. Therefore, there is a problem in that the solder balls in other portions do not uniformly contact the solder paste printed on the mounting board, and there is a high risk of failure due to non-connection. Japanese Patent Application Laid-Open No. 9-162241 also discloses a conventional technique in which reinforcing projections are provided at four corners of a semiconductor package.

Japanese Patent Application Laid-Open No. 9-205113 discloses a conventional technique based on a concept similar to those of the prior art. A configuration for reliably performing welding during the period is disclosed. According to this technique, since the amount of solder in the reinforcing film is sufficiently larger than that in the solder bump, fatigue fracture can be prevented, and an optimum fillet shape can be obtained due to the effect of surface tension during welding. However, since the amount of solder between the solder bumps and the reinforcing film is overwhelmingly different, it is undeniable that uneven connection may occur at the time of welding, particularly at the solder ball portion.

As a prior art relating to a mounting structure of a BGA type semiconductor package, there is a technology relating to a structure for preventing a void contained in a welded portion of a solder ball (Japanese Patent Laid-Open No. 10-270856). This is an improved pad structure of a multilayer wiring board. BGA
In order to prevent positional displacement when mounting electronic components of a mold, there is also known a technology for providing a through hole on the electronic component side and providing a pad on the printed wiring board side so as to match the two (Japanese Patent Laid-Open No. HEI 9-163572). 9-205113). However, in this case, it merely functions as a positioning mark, and does not contribute to an electrical or physical bonding state.

[0010]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art and can improve the electrical or physical bonding state of a BGA type semiconductor package or an LGA type semiconductor package. And a mounting structure thereof.

[0011]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a semiconductor package substrate in which at least two corners are provided with reinforcing leads for ensuring fixation between the semiconductor package substrate and a mounting substrate so that bonding after mounting is achieved. The problem is solved by a BGA type semiconductor package or an LGA type semiconductor package which improves strength and reliability.

Further, an open end of a reinforcing lead provided at a corner of a substrate of a BGA type semiconductor package or an LGA type semiconductor package is inserted into a through hole formed before mounting on a mounting substrate. BGA soldered to the surface without using
The problem is solved by a mounting structure of a semiconductor package or an LGA semiconductor package.

The BGA type semiconductor package or the LGA type semiconductor package according to the present invention has reinforcing lead terminals which exhibit a reinforcing function after mounting at at least two corners on the semiconductor package side. Then, these are fixed to the through-holes of the mounting board or the surfaces thereof by soldering, thereby protecting the BGA-joined terminals as reinforcement against external mechanical stress or thermal stress.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be disclosed below with reference to the accompanying drawings. However, the present invention is not limited by the embodiment. As shown in FIG. 1, the BGA type semiconductor package 1 of the present invention has a reinforcing lead mounting hole 3 at at least diagonal corners, preferably at four corners of the substrate 2, and this hole 3 As shown in the side view, the reinforcing lead 6 is joined in advance. Reference numeral 4 denotes a semiconductor sealing portion, and reference numeral 5 denotes a solder ball. The reinforcing lead 6 may be attached by any means such as soldering with high melting point and bonding. However, in addition to the purpose of reinforcement, in the case where an electric function such as a power supply and a ground is provided between the mounting board and the mounting board. In this case, the reinforcing lead mounting hole 3 may be a through-hole, and the bonding method may be a method that enables electrical connection.

FIG. 3 is a side sectional view showing a state in which the BGA type semiconductor package 1 according to the present invention is mounted on a mounting substrate 7. As shown in FIG. As shown in this figure, the electrical connection with the mounting board 7 is made by a solder ball 5 as in the conventional case, and the reinforcing lead 6 is soldered to a through through hole 8 provided at a predetermined position of the mounting board 7. . Even if an insertion terminal such as the reinforcing lead 6 is provided, the conventional automatic mounting is possible after printing the solder paste on the through-hole land portion. Thereby, the reinforcing lead 6
Protects solder ball joints from external stress after mounting, and greatly improves durability and reliability.

In this case, the reinforcing leads 6 are
Is described as being attached to the BGA type semiconductor package 1. However, the through holes formed in advance in the semiconductor package 1 are automatically mounted in accordance with the through holes on the mounting board 7, and after the mounting is completed, the package and the mounting board are mounted. 7
The same effect can be obtained by inserting the reinforcing lead 6 into both through holes and soldering them.

Next, a method of mounting the BGA type semiconductor package shown in FIGS. 1 and 2 will be described with reference to the drawings.
Referring to FIG. 4, a solder paste 9 is supplied not only to the BGA land portion but also to the through-hole 8 to the mounting substrate 7 by a screen printing method or a dispensing method. Next, the BGA type semiconductor package 1 of the present invention is mounted at a predetermined position by a well-known mounting machine.

The solder paste 9 supplied to the through-hole 8 is pushed in by the reinforcing lead 6 being inserted into the through-hole 8, and goes around the back side of the mounting board 7. Finally, by reflow heating, FIG.
As described above, the solder balls 5 and the reinforcing leads 6 are respectively soldered, and the mounting is completed.

Thus, the soldering portion of the reinforcing lead 6 securely fixes the BGA type semiconductor package 1 and the mounting board 7. Therefore, the soldered portions of the solder balls 5 at the inner portions surrounded by the reinforcing leads 6 are protected from mechanical or thermal external stress, and the strength and reliability after mounting are greatly improved. be able to.

Next, referring to FIG. 5 showing another embodiment of the present invention, the substrate 2 has no reinforcing lead mounting hole, and the reinforcing lead 6 is fixedly fixed at a predetermined position on the surface of the substrate 2. . In this embodiment, since there is no need for mounting holes in the substrate 2, there is a new effect that the size of the BGA type semiconductor package can be reduced as compared with the embodiment of FIG.

Referring to FIG. 6 showing still another embodiment, the connection side with the mounting substrate at the open end below the reinforcing lead 6 is also of a surface mounting type. This embodiment has a new effect that a through-hole is not required in the mounting substrate. Further, in this embodiment, the reinforcement lead 6 has been described as being mainly fixed to the BGA type semiconductor package in advance. However, after mounting the BGA type semiconductor package, the similar reinforcement lead is soldered or similar. The same effect can be obtained even when fixing.

Further, in all of the above embodiments, the BGA
Type semiconductor package, but LGA
Exactly the same effect can be obtained in a (land grid array) type semiconductor package.

[0023]

According to the ball grid array type semiconductor package and the mounting structure thereof according to the present invention, the following effects can be obtained. The first effect is that the connection strength and reliability after mounting are greatly improved. For this reason, in the device design, restrictions on the mounting position and mechanical reinforcement components are not required.

The second effect is that the work in the post-mounting process is not required. Conventionally, in devices that require high reliability and portable devices that are easily exposed to external stress, in the post-mounting process, resin is applied to the periphery of the BGA package and the gap on the back surface and cured to increase the strength and life. Although improved, these tasks can be reduced. As a result, effects such as a reduction in manufacturing lead time and a reduction in processing cost can be expected. Further, since the heating at the time of curing the resin is not required, an effect of preventing the quality deterioration of the mounting board and the mounted components can be expected.

[Brief description of the drawings]

FIG. 1 is a plan view of a BGA type semiconductor package according to the present invention.

FIG. 2 is a side sectional view of a BGA type semiconductor package according to the present invention.

FIG. 3 is a side sectional view showing a state in which the BGA type semiconductor package according to the present invention is mounted on a mounting board.

FIG. 4 is a side sectional view showing a state before a BGA type semiconductor package according to the present invention is mounted on a mounting board.

FIG. 5 is a side sectional view showing another embodiment of the BGA type semiconductor package according to the present invention.

FIG. 6 is a side sectional view showing still another embodiment of the BGA type semiconductor package according to the present invention.

[Explanation of symbols]

 1: BGA type semiconductor package 2: Substrate 3: Reinforcement lead mounting hole 4: Semiconductor sealing portion 5: Solder ball 6: Reinforcement lead 7: Mounting substrate 8: Through-hole 9: Solder paste

Claims (7)

[Claims] 1. A BGA type semiconductor package or an LGA type semiconductor package comprising a reinforcing lead at at least two corners of a semiconductor package substrate for ensuring fixation between the semiconductor package substrate and a mounting substrate. 2. The BGA type semiconductor package according to claim 1, wherein the reinforcing leads are provided at all corners of the semiconductor package substrate.
GA type semiconductor package. 3. The semiconductor device according to claim 1, wherein the reinforcing lead is attached via a through hole formed in the semiconductor package substrate.
The BGA type semiconductor package or the LGA type semiconductor package according to any one of the above. 4. The BGA type semiconductor according to claim 1, wherein the reinforcing lead is attached to the semiconductor package substrate without forming a through hole. Package or LGA type semiconductor package. 5. A BGA type semiconductor package or LG
A BGA type semiconductor package characterized in that an open end of a reinforcing lead provided at a corner of a substrate of an A type semiconductor package is inserted into a through hole formed in advance when mounted on a mounting substrate and soldered, or LG
Mounting structure of A-type semiconductor package. 6. A BGA type semiconductor package or LG
A mounting structure of a BGA type semiconductor package or an LGA type semiconductor package, wherein an open end of a reinforcing lead provided at a corner of a substrate of an A type semiconductor package is soldered to a predetermined portion on a surface of a mounting substrate. 7. The mounting structure of a BGA type semiconductor package or an LGA type semiconductor package according to claim 6, wherein the reinforcing lead of the semiconductor package has a function of an electrical connection member in addition to mechanical reinforcement. .